Authors:

Abstract

Background

The outcome of radioactive iodine therapy with I-131 (RAI) therapy is influenced by many factors. Pretreatment with antithyroid drugs (ATD) is considered as one of the factors affecting the outcome. Carbimazole and methimazole are shown to be having lesser effect on outcome of RAI therapy compared to propylthiouracil.

Objective

This study was aimed to identify the difference in the pre-treatment carbimazole dose and duration among patients with various outcomes after radioiodine therapy for hyperthyroidism.

Methodology

Fifty hyperthyroid patients consented for the study after receiving 10 mCi RAI and they were followed up to monitor the clinical outcome at Nuclear Medicine Unit, Peradeniya. Therapeutic outcome was assessed at 03 and 06 months after RAI therapy by clinical assessment and biochemical thyroid function tests (free thyroxine (fT4) and TSH levels). The data were analyzed using SPSS version 25.

Results

Graves’ disease was high (70%) among participants compared to toxic multinodular goiter (30%). Six months after RAI therapy, 84% of the patients responded to the treatment and 16% had persistent hyperthyroidism. The mean daily dose (P=0.193) and mean duration (P=0.563) of carbimazole treatment between these two outcomes didn’t show a signigficant difference.

Conclusion

Keywords: Hyperthyroidism, Graves’ disease, Toxic multi Nodular goiter, Radioactive iodine, Carbimazole